Rotary take-up for sewing machines



v A. DJ SMITH. v ROTARY TAKE-UP FOR SEWING MACHINES.

APPLICATION FILED AUG. 20, ms.

1 ,41 5 ,269, Patented May 9,1922.

' special ALBERT D. SMITH, OF

rim

FE'KQE.

DETROIT, MICHIGAN.

ROTARY TAKE-"U1? FOR SEWING MACHINES.

Application filed August 2O,v 1918. Serial No. 250,651.

To all whom it may concern:

Be it known that I, ALBERT D. SMITH, a citizen of the United States, residing at Detroit, in the county of Wayne and State of Michigan, have invented certain new and useful Improvements in Rotary Take-Ups for Sewing Machines, of which the following is a specification.

, This invention relates in general to sewing machines, and the primary object is to provide a rotary take-up of simplified and generally improved construction with the view to accomplishing certain desired results.

For example, it has heretofore been necessary in the use of rotary take-ups to provide mechanism for regulating the amount or length of thread given down at each stitch in accordance with the thickness of the goods. It has also been necessary to provide special devices, spring-actuated controllers, differential driving mechanism, etc, for controlling the slack thread in the takeup at certain times in the operation. These special devices not only complicated a sewingmachine and increased the cost of production, but very frequently were so impractical as to cause the thread to become wound in the take-up and broken. It is to overcome these deficiencies that my present rota-ry take-up has been designed.

One of the features of my present invention is the provision of an improved takeup which enables goods of any thicknessto be sewed without the provision of special devices for varying the length of thread given down for the different thicknesses of goods. At the same time, perfect stitches are obtained under all circumstances Other objects and attendant advantages will be appreciated as the invention becomes better understood by reference to the following description when considered in connection with the accompanying drawings, in which I Figure 1 is an end elevation of a sewing machine head having a rotary take-up embodying my improvements;

Figs. 2 and 3, vertical sectional Views taken substantially on the lines 2-2 and 33, respective1y,of Fig. 1;

Figs. 4; and 5 horizontal sectional views taken substantially on the lines 4- 1 and 55, respectively, of Fig. 1;

Fig. 6, a side View looking at the left hand side of Fig. 1; and a Fig. 7 a development of the annular wall that clrcumscribes the take-up disks.

My present improvement is illustrated in connection with a sewing machine of the rotary hook type, and the parts not necessary for an understanding of the invention have been omitted. The well known parts comprise the work table 9, rotary hook 11, machine head 12, needle bar 13, presser bar 114: and the lever 15 for liftingthe presser On the end of the machine head 12, I have secured in a suitable manner, a cover plate designated generally by character 16,.shaped to provide a casing 17 for the rotary takeup disks 18 and 19. This casing is provided .with a peripheral wall or flange of novel shape to provide certain thread-guiding-surfaces, the purpose of which will presently appear.

The take-up proper consists of the disks 18 and 19 connected together by but a single eccentric thread-engaging means or pin 21, preferably of relatively large diameter. These disks are positionedin comparatively close relation as shown, and the inner disk 18 is fixed to a hub 22 adapted to be secured to the needle-bar driving shaft or an extension thereof, so that thetake-up disks are rotated directly with said driving shaft- In the present case, the rotary hook 11 is revolved three times to each revolution of the take-up,

and when the needle is at its highest point the disks. ,The thread guides are positioned in certain relation to and co-operate with the threadguiding surfaces formedv by the annular wall. or flange of the casing 17, the shape and purpose of which surfaces will now be described.

As clearly shown in the drawings, the annular casing wall designated generally by character 25, is formed at its lowermost point in the perpendicular plane of the needle with a cutaway providing what may be termed a low surface 26 substantially flush with the outer surface of the disk 18. The take-up revolves in a clockwise direction; and as shown clearly in Figs. 3 to 6 inclusive, that portion of the wall 25 at the intake Side of the take-up gradually increases in depth from the point 26 to a high point 27, providing a gradually inclinedthread-guiding surface 28 which crosses obliquely the space between the rotary disks. As shown in Fig. '6, the wall 27 decreases in height as it approaches the uppermost point 29 of the easing, although this is not essential to the operation, and thdpurpose is simply to give "access to the space between the disks at this point. Viewing Figs. 2, 6 and 7, it will be noted that the wall at the descending side of the take-up gradually increases in depth and terminates inan abriuot shoulder 31 at the lowermost point in the take-up. It will be further noted that the portion 32 or the wall extends a substantial distance beyond the outermost disk and also beyond the thread guide 24. The function oi this wall portion 32 is very important, since by its use I am enabled to dispense with various auxiliarydevices which have been heretofore necessary for controlling the slack thread and also for re'gulatin'g the amount oi thread given down for sewing goods of different thicknessf Regarding the thread-guiding staple 24:, it will be noted. that this staple is so positioned as to hold the outgoing thread in line with the needle and to also impose a slight tension on. this thread so as to prevent the thread from falling freely from between thetake-u-p disks. The purpose of imposing this slight tension on the out oing thread at this point will be more readily apparent after a consideration 'o'fthe complete operation.

The present take-up is designed to produce a relatively large slack of thread necessary to be passed around-an unusually large lower thread receptacle oi the character described in my co-pending application, Serial No. 247,423, filed July 230, 19-1-8, and because of therelativetiming of the rotary hook and take-up necessitated by revolving these parts at a uniform speed asdistin'guished from a 'd-iiierential speed, a large slack of thread is momentarily produced in the takeup. This slacker" thread must be properly controlled at this instant, otherwise the threadwillinvariably cause the rotary hook to foul or will become wound in the take-up or caught on some stationary part, thereby resulting in breaking of the thread. Such an occurrence is preventedby reason of the peculiarly shaped wall portion or pocket 32 at the lower descending side of the take-up 'and by the manner in which the thread leaves thetake-up under the nfluence or a slight tension imposed by the staple 24:. As

shown in Fig. 1, the upper spool thread is passed beneath the staple 23, and guided :goods.

along the surface 28,'it enters beneath the outermost diskl9 and passes over the eccentric stud 21, it being noted that there is sufiicient clearance between the periphery of the cisk 1'9 and the internal surface or the wall 25 to permit passage or the thread between this disk and entirely around the takeup in a clockwise direction untilthe point 26 is reached, whereupon the thread is passed beneath the staple 24:, which is'disposed al most entirely beneath the pocket portion 32 of the thread-controlling wall. The thread now leaves the take-up directly above the needle at all times. I When the take-up pin 21 reaches approximately the point A, Fig. 1, there'is a maximum of slack loose thread between the disks which. loose thread,

due to centrifugal force, is thrown out-- wardly and strikes the wall 32. This wall as shown, extends a substantial distance outwardly from the OIltGI'IHOSiBCl'lSk and conoutgoing thread. passing over the edge 31' and beneath the staple 2e prevents thisslack thread from falling from the take-up and.

interfering with the control of the thread between the take-up and the rotary hook.

By reason of the foregoing construct-ion, it

is not necessary to provide auxiliary means for varying the amount of thread given down whensewing goods or different thickness. As a result, perfect stitches are obtained without adjustment-orany kind, regardless of the thickness or the goods. The take-up is so proportioned and timed thatthe thread is just taut when the needle enters the finest From this instant, the takeup pin descends atthe rate of about 14 times the speed of the needle and produces the proper amount of slack for the heavy goods. Thus 7 no auxiliary means is necessary to varyv the amount of slack given down when goods of different thickness are sewed, because in the present instance the surplus slack when sewing thin goods is fully controlled. and sufiicicnt amount ot'slack is produced at all times to sew goods of any thickness.

It is believedthat the foregoing conveys a clear understanding or my improvement, and it should be understood that whlle I have illustrated and described a single working embodiment thereof, changes might bemade in the proportions and arrangement of parts without departing from the, spiritiand scope of the invention as expressed in the appended claims.

I claim:

1. A rotary take-up structure for sewing machines comprising a pair or rotary disks connected by an eccentric thread-engaging means, thread guides at the underside of the take-up as 1t enters between and leaves the disks so that a comparatively large slack of thread is produced, and means for controlling the slack thread when the eccentric thread-engaging means descends, comprising a casing for the rotary disks open at the front thereof and having an annular wall at the descending side of the disks extending outwardly a substantial distance beyond the outermost disk.

2. In a sewing machine, the combination with the head, of an end plate on the head having an annular outstanding flange, a pair of revoluble disks disposed within said annular flange and connected together by but a single eccentric thread engaging means, the lower flange portion at the descending side of the take-up disks being extended out wardly a substantial distance beyond the outer disk and cut away substantially in the perpendicular plane of the needle and directly below the space between the disks, the flange being further cut away on its opposite lower portion to provide an outer surface extending at a gradual inclination outwardly and upwardly from below said space between the disks, and thread guiding means for guiding the thread to pass over said second cutaway to enter between the disks and to leave the disks through said first cutaway.

3. In a sewing machine, the combination of a pair of rotary take-up disks, thread takeup means interposed between the disks leaving a substantially uninterrupted thread compartment therebetween, thread-guiding means for causing the thread to enter and leave said compartment from the underside of the disks, and a wall circumferentially about and in close proximity to the periphery of the disks constituting an outer wall to said compartment and shaped at the lower descending side of the take-up to extend substantially beyond the outer disk for controlling the slack thread substantially as described.

ALBERT D. SMITH. 

